Technical Abstract:
To examine whether there is a relationship between the degree of Campylobacter contamination observed in product lots of retail Icelandic broiler chicken carcasses and human disease, isolates from individual product lots were genetically matched (using flaA Short Variable Region) to isolates from cases of human campylobacteriosis whose onset was within approximately two weeks from the date of processing. When there was genetic identity between broiler isolates and human isolates from the appropriate time frame, a retail product lot was classified as implicated in human disease. From this analysis, there were multiple clusters of human disease linked to the same process lot or lots. Retail product lots were also characterized in the laboratory by rinse-direct plating methods to obtain lot mean contamination, maximum contamination, and prevalence. For all three lot descriptors, Mann-Whitney U tests showed that implicated product lots had significantly higher values than non-implicated lots for product distributed both as fresh (mean contamination: P = 0.0007; maximum contamination: P = 0.0212; prevalence: P = 0.0099) and as frozen (P = 0.0212, P = 0.0446, and P = 0.0314, respectively). Our results suggest that broiler-borne campylobacteriosis can occur in outbreaks and that the differences in prevalence and contamination levels may provide a basis for regulatory action other than a presence/absence standard.